Chromium

Chromium is a a naturally occurring element found in rocks, animals, plants, soil, volcanic dust and gas. In the periodic table, its symbol is Cr and its atomic number 24. It is odorless and tasteless. Chromium can be found in a number of different forms including trivalent (chromium-3), hexavalent (chromium-6), and the metal form, chromium 6.

Chromium-3 is an essential nutrient in humans and it is often added to vitamins as a dietary supplement. Chromium-3 occurs naturally in many vegetables, fruits, meats, grains and yeast. However, hexavalent chromium is toxic and carcinogenic. In its hexavalent (chromium 6+) form, chromium has been found in sewage sludge, as well as coal waste. The U.S. EPA prohibits chromium in drinking water above a concentration of 0.1 mg/L or 100 ppb (parts per billion). Chromium may not exceed 3000 ppm in sewage sludge applied to land as fertilizer. In the Targeted National Sewage Sludge Survey, a 2009 test of 84 samples of sewage sludge from around the U.S., the EPA found chromium in every sample in concentrations ranging from 6.74 to 1160 parts per million.

Uses
Chromium-0 is used mainly for making steel and other alloys. Chromium compounds, in either the chromium-3 or -6 forms, are used in dyes and paints industry and therefore these compounds are often found in soil and groundwater at abandoned industrial sites.

Toxicity
Most significantly, chromium is a carcinogen. Inhalation of chromium-6 has been shown to cause lung cancer. Additionally, an increase in stomach tumors was observed in humans and animals exposed to chromium-6 in drinking water. Breathing high levels of chromium-6 can also cause irritation to the lining of the nose, nose ulcers, runny nose, and breathing problems, such as asthma, cough, shortness of breath, or wheezing. If ingested, chromium-6 compounds can cause irritation and ulcers in the stomach and small intestine and anemia. Skin contact with certain chromium-6 compounds can cause skin ulcers. According to the Centers for Disease Control, "Sperm damage and damage to the male reproductive system have also been seen in laboratory animals exposed to chromium-6.

Erin Brokovich
Erin Brockovich is well-known for helping uncover the presence of extraordinarily high levels of industrial hexavalent chromium contamination in the drinking water of a small town ravaged by cancer. The case began in 1993, when residents of Hinkley, California, brought documentation of chromium contamination in their groundwater to a law firm, which passed the file to Brockovich, leading to a 1996 settlement.

Many of the more than 600 original Hinkley litigants moved away from the town after the settlement, but some stayed, relocating a few miles away. PG&E was required to clean up the contaminated water, but in 2008, the plume of chromium began spreading. Despite efforts by PG&E to stem the problem, tests in 2011 showed it was growing again. According to PG&E, the plume is two miles long and a mile wide. In January 2011, Brokovich returned to the town and began testing the water with Bob Bowcock of Integrated Resource Management. By March, they had taken about 180 water samples. Bowcock, the former utility director, said the tests reveal that the contaminated area is twice as big as PG&E's estimates.

Bowcock said there may be contamination well beyond the original plume boundaries because decades earlier, when pumping at nearby farms caused some residents' well levels to fall, that water might have been unknowingly replaced with thousands of gallons of chromium-laced water. Bowcock also said they have found much higher pollution levels than expected. Some areas, he said, are showing levels that are 400 times higher than the recommended public health goal. While the utility believes the contamination is affecting an estimated 100 households, he believes the number is closer to 250. Brockovich and Bowcock expect to share some of the details at an upcoming Lahontan Regional Water Quality Control Board meeting.

Regulations
The U.S. EPA prohibits chromium in drinking water above a concentration of 0.1 mg/L or 100 ppb (parts per billion). In December 2010, the Environmental Working Group released a report documenting the cancer-causing chemical in tap water in 31 of 35 cities tested in the United States. Days later, on December 31, 2010, the California Office of Environmental Health Hazard Assessment (OEHHA) completed a multi-year, peer- reviewed examination of the oral toxicity of the chemical, involving scientists in both the public and private sectors, and proposed reducing the maximum for hexavalent chromium in drinking water to just 0.02 parts per billion (or ug/L), or 5,000 times lower than the federal drinking water standard for total chromium. On January 11, 2011, the U.S. Environmental Protection Agency (EPA) issued new guidelines recommending that public water utilities nationwide test drinking water for hexavalent chromium.

The 2011 report, "EPA’s Blind Spot: Hexavalent Chromium in Coal Ash: Coal ash may be the secret source of cancer-causing chromium in your drinking water", suggests the EPA also establish tests and regulations for coal ash, as the EPA’s latest 2009 report on the hazardous contaminants in coal ash found that:
 * Coal ash leaches chromium in amounts that can greatly exceed EPA’s threshold for hazardous waste at 5000 parts per billion (ppb); and
 * The chromium that leaches from coal ash is “nearly 100 percent [hexavalent] Cr(VI).”

There are also no U.S. regulations for chromium concentrations in sewage sludge applied to land. In the Targeted National Sewage Sludge Survey, a 2009 test of 84 samples of sewage sludge from around the U.S., the EPA found chromium in every sample in concentrations ranging from 6.74 to 1160 parts per million.

Related SourceWatch articles

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 * Sewage sludge
 * Food Rights Network
 * Heavy metals and coal